Soil fauna (excluding pests) and flora (excluding soil-borne plant pathogens); soil-plant-animal

relationships;

Soil bacteriology and microbiology: ammonification, nitrification, denitrification, nitrogen-fixation,

inoculation, root nodulation, decomposition of non-nitrogenous compounds, conversion of inorganic

substances, rhizobia, mycorrhiza;

Soil biochemistry;

Decomposition of litter; humus.

For: physiological aspect of symbiotic phenomenon, see F61

plant pests in soil, see H10

soil-borne plant pathogens, see H20

soil sterilization and hygiene, see F07